JP5581781B2 - Method for manufacturing piezoelectric actuator - Google Patents

Description

  The present invention relates to a method for manufacturing a piezoelectric actuator including a piezoelectric element having a piezoelectric body made of an individual electrode and a piezoelectric material, and an extraction electrode connected to the individual electrode.

  2. Description of the Related Art Known piezoelectric actuators include a piezoelectric element having a lower electrode, a piezoelectric body, and an upper electrode, and an extraction electrode connected to each electrode of the piezoelectric element. A piezoelectric element includes a piezoelectric material having an electromechanical conversion function, for example, a piezoelectric body made of crystallized piezoelectric ceramics or the like, sandwiched between two electrodes, a lower electrode and an upper electrode.

  As a manufacturing method of the piezoelectric actuator, the laminated lower electrode film, piezoelectric layer, and upper electrode film are patterned by dry etching such as reactive ion etching or ion milling, and the piezoelectric material having the lower electrode, piezoelectric body, and upper electrode is obtained. A manufacturing method is known in which an element is formed, and then an extraction electrode is formed on each upper electrode that is an individual electrode (for example, see Patent Document 1).

JP 2009-255526 A (page 9, FIG. 6)

If particles adhere to the upper electrode film before or during dry etching, the lower electrode film, the piezoelectric layer, and the upper electrode film where the particles have adhered remain without being etched.
Of the lower electrode film, the piezoelectric layer, and the upper electrode film remaining outside the piezoelectric element formation portion, the etching residue straddling between the extraction electrodes to be formed later passes through the upper electrode film when the extraction electrode is formed. This causes a short circuit between the extraction electrodes. Therefore, the insulation between the extraction electrodes is not maintained, and a drive failure of the piezoelectric actuator occurs due to a short circuit.

  The present invention has been made to solve the above-described problems, and can be realized as the following forms or application examples.

[Application Example 1]
A method for manufacturing a piezoelectric actuator comprising a piezoelectric element having either a lower electrode or an upper electrode as an individual electrode and an extraction electrode drawn from the individual electrode, wherein a lower electrode film is formed on a substrate. An electrode film forming step, a piezoelectric layer forming step of forming a piezoelectric layer on the lower electrode film, an upper electrode film forming step of forming an upper electrode film on the piezoelectric layer, the piezoelectric layer and the A piezoelectric element forming step of selectively etching the lower electrode film or the upper electrode film to form the piezoelectric element including either the piezoelectric body or the lower electrode or the upper electrode as the individual electrode; An etching step of etching at least a part of the substrate between the extraction electrodes under the condition that the upper electrode film is removed and the substrate is not removed after the piezoelectric element forming step; After packaging process, the manufacturing method of the piezoelectric actuator, characterized in that it comprises a lead electrode formation step of forming the extraction electrode drawn from each of the individual electrodes.

  According to this application example, in the etching process, at least a part of the substrate between the extraction electrodes formed in the extraction electrode forming process is etched under the condition that the upper electrode film is removed and the substrate is not removed. Even if an etching residue including the upper electrode film is generated between the extraction electrodes during the piezoelectric element forming step, the upper electrode film is divided by etching, and insulation between the extraction electrodes formed on the upper electrode film is maintained. Therefore, a method for manufacturing a piezoelectric actuator with reduced drive failure of the piezoelectric actuator caused by a short circuit between the extraction electrodes can be obtained.

[Application Example 2]
The method for manufacturing a piezoelectric actuator according to claim 1, wherein, in the etching step, the space between the extraction electrodes is etched along the extraction electrodes to form a slit in the substrate.
In this application example, a slit is formed between the extraction electrodes along the extraction electrode. Therefore, regardless of where the etching residue including the upper electrode film occurs between the extraction electrodes, the upper electrode film is divided and between the extraction electrodes. Insulation is maintained. Therefore, a piezoelectric actuator manufacturing method can be obtained in which drive failure of the piezoelectric actuator caused by a short circuit between the extraction electrodes is further reduced.

[Application Example 3]
In the piezoelectric actuator manufacturing method, the piezoelectric element forming step includes forming the lower electrode as a common electrode on the substrate, selectively etching the piezoelectric layer and the upper electrode film, A method of manufacturing a piezoelectric actuator, comprising forming the piezoelectric element including a piezoelectric body and the upper electrode as the individual electrode.
In this application example, in the piezoelectric actuator in which the lower electrode formed on the diaphragm is the common electrode and the upper electrode formed on the piezoelectric body is the individual electrode, a method for manufacturing the piezoelectric actuator having the above-described effect can be obtained.

Schematic which shows an example of an ink jet recording device. FIG. 3 is an exploded partial perspective view showing an ink jet recording head. (A) is a partial top view of an ink jet recording head, (b) is an AA cross-sectional view in (a). The flowchart figure showing the manufacturing method of an inkjet recording head. (A)-(d) is sectional drawing of the longitudinal direction of the pressure generation chamber showing the manufacturing method of an inkjet recording head. (E)-(h) is sectional drawing of the longitudinal direction of the pressure generation chamber showing the manufacturing method of an inkjet recording head. (I)-(k-1) is sectional drawing of the longitudinal direction of the pressure generation chamber showing the manufacturing method of an inkjet recording head. (K-2)-(m) is sectional drawing of the longitudinal direction of the pressure generation chamber showing the manufacturing method of an inkjet recording head. (N) And (o) is sectional drawing of the longitudinal direction of the pressure generation chamber showing the manufacturing method of an inkjet recording head. (P)-(r) is sectional drawing of the longitudinal direction of the pressure generation chamber showing the manufacturing method of an inkjet recording head. The fragmentary top view in the state of FIG.6 (h) when a particle adheres. FIG. 6H is a partial cross-sectional view in the state of FIG. 6H when particles are attached, FIG. 11A is a partial cross-sectional view along BB in FIG. 11, and FIG. FIG. 7A is a partial cross-sectional view in the state of FIG. 7I when particles are attached, FIG. 11A is a partial cross-sectional view along BB in FIG. 11, and FIG. 7 (k-1) and FIG. 8 (k-2) when the particles are attached, (a) is a partial cross-sectional view taken along the line BB in FIG. 11, and (b) is FIG. CC sectional view taken on the line. 8A is a partial cross-sectional view in the state of FIG. 8L when particles are attached, FIG. 8A is a partial cross-sectional view along BB in FIG. 11, and FIG. 8B is a partial cross-sectional view in the state of FIG. 8M when particles are attached, FIG. 11A is a partial cross-sectional view along BB in FIG. 11, and FIG.

Hereinafter, embodiments will be described in detail with reference to the drawings.
FIG. 1 is a schematic diagram illustrating an example of an ink jet recording apparatus 1000 as a liquid ejecting apparatus including an ink jet recording head 1 as a liquid ejecting head including a piezoelectric actuator.
As shown in FIG. 1, the ink jet recording apparatus 1000 includes recording head units 1A and 1B.
The recording head units 1A and 1B are detachably provided with cartridges 2A and 2B constituting ink supply means. A carriage 3 on which the recording head units 1A and 1B are mounted is a carriage shaft 5 attached to the apparatus main body 4. Are provided so as to be axially movable.

  The recording head units 1A and 1B eject, for example, a black ink composition and a color ink composition, respectively. Then, the driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears and a timing belt 7 (not shown), so that the carriage 3 on which the recording head units 1A and 1B are mounted is moved along the carriage shaft 5. The On the other hand, the apparatus body 4 is provided with a platen 8 along the carriage shaft 5, and a recording sheet S that is a recording medium such as paper fed by a paper feed roller (not shown) is conveyed on the platen 8. The

  The recording head units 1 </ b> A and 1 </ b> B include the ink jet recording head 1 at a position facing the recording sheet S.

FIG. 2 is an exploded partial perspective view showing the ink jet recording head 1. The shape of the ink jet recording head 1 is a substantially rectangular parallelepiped, and FIG. 2 is an exploded partial perspective view cut along a plane orthogonal to the longitudinal direction of the ink jet recording head 1 (the direction of the white arrow in the figure).
3A is a partial plan view of the ink jet recording head 1, and FIG. 3B is a cross-sectional view taken along line AA.

2 and 3, the ink jet recording head 1 includes a flow path forming substrate 10, a nozzle plate 20, a bonding substrate 30, a compliance substrate 40, and a driving IC 400.
The flow path forming substrate 10, the nozzle plate 20, and the bonding substrate 30 are stacked such that the flow path forming substrate 10 is sandwiched between the nozzle plate 20 and the bonding substrate 30, and the compliance substrate 40 is formed on the bonding substrate 30. ing. A driving IC 400 is mounted on the bonding substrate 30.

  The flow path forming substrate 10 is made of a silicon single crystal plate having a plane orientation (110). A plurality of pressure generating chambers 12 are formed in the flow path forming substrate 10 in a row. The cross-sectional shape of the pressure generating chamber 12 orthogonal to the longitudinal direction of the ink jet recording head 1 is trapezoidal, and the pressure generating chamber 12 is formed long in the width direction of the ink jet recording head 1.

  Further, an ink supply path 13 is formed at one end in the width direction of the pressure generation chamber 12 of the flow path forming substrate 10, and the ink supply path 13 and each pressure generation chamber 12 are provided for each pressure generation chamber 12. The communication unit 14 communicates with the communication unit 14. The communication portion 14 is formed with a narrower width than the pressure generation chamber 12, and maintains a constant flow path resistance of ink flowing into the pressure generation chamber 12 from the communication portion 14.

The nozzle plate 20 has a nozzle opening 21 communicating with the vicinity of the end of each pressure generating chamber 12 on the side opposite to the ink supply path 13.
The nozzle plate 20 has a thickness of, for example, 0.01 to 1 mm, and is made of glass ceramics, a silicon single crystal substrate, non-rust steel, or the like.
The flow path forming substrate 10 and the nozzle plate 20 are fixed by an adhesive, a heat welding film, or the like.

An elastic film 50 is formed on the surface of the flow path forming substrate 10 that faces the surface to which the nozzle plate 20 is fixed. The elastic film 50 is made of a film containing silicon oxide.
An insulating film 51 made of an oxide film is formed on the elastic film 50 of the flow path forming substrate 10. Further, a lower electrode 60, a perovskite structure piezoelectric body 70, and an upper electrode 80 are formed on the insulator film 51, thereby constituting a piezoelectric element 300. Here, the piezoelectric element 300 refers to a portion including the lower electrode 60, the piezoelectric body 70, and the upper electrode 80.

In general, one of the electrodes of the piezoelectric element 300 is used as a common electrode, and the other electrode is used as an individual electrode, which is patterned for each pressure generating chamber 12 together with the piezoelectric body 70. In addition, here, a portion that is configured by any one of the patterned electrodes and the piezoelectric body 70 and in which piezoelectric distortion is generated by applying a voltage to both electrodes is referred to as a piezoelectric active portion.
In the present embodiment, the lower electrode 60 is a common electrode of the piezoelectric element 300 and the upper electrode 80 is an individual electrode of the piezoelectric element 300. However, there is no problem even if this is reversed for the convenience of the drive circuit and wiring. In either case, a piezoelectric active part is formed for each pressure generating chamber 12.

2 and 3, an extraction electrode 90 is formed on each upper electrode 80 constituting each piezoelectric element 300.
Here, the piezoelectric element 300, the elastic film 50 that is displaced by driving the piezoelectric element 300, the insulator film 51 (the two films are collectively referred to as the diaphragm 53), and the extraction electrode 90 are collectively referred to as a piezoelectric actuator 100. The lower electrode 60 is formed on a diaphragm 53 as a substrate.

A slit 91 is formed between the extraction electrodes 90. The slits 91 are formed in the insulator film 51 or up to the elastic film 50, and a plurality of slits 91 are formed between the extraction electrodes 90.
The slit 91 is formed along at least one part of the diaphragm 53 between the adjacent extraction electrodes 90 along the extraction electrode 90. In the present embodiment, the extraction electrode 90 is formed from the portion where the upper electrode 80 is formed to the outer periphery of the insulator film 51. Here, the slit 91 is formed shallower than the thickness of the diaphragm 53.

On the vibration plate 53 to which the bonding substrate 30 is bonded, step adjusting portions 310 and 320 having the same layer structure as the piezoelectric element 300 are formed.
The step adjustment unit 310 is formed at a position between the ink supply path 13 and the piezoelectric element 300, and the step adjustment unit 320 is formed at a position facing the step adjustment unit 310 with the ink supply path 13 interposed therebetween.
The step adjustment unit 310 is composed of the lower electrode film 61, the piezoelectric layer 71, and the upper electrode film 81, and the step adjustment unit 320 is composed of the lower electrode film 62, the piezoelectric layer 72, and the upper electrode film 82.
Here, a slit 311 for relieving stress is formed in the upper electrode film 81 of the step adjusting section 310 in the longitudinal direction of the ink jet recording head 1.

On the flow path forming substrate 10 on which the piezoelectric element 300 is formed, the bonding substrate 30 is bonded by an adhesive 35.
The bonding substrate 30 has a piezoelectric element holding portion 32 that can seal the space in a region facing the piezoelectric element 300 in a state where a space that does not hinder the movement of the piezoelectric element 300 is secured. The piezoelectric element holding portions 32 are provided corresponding to the rows of the pressure generating chambers 12.

In the present embodiment, the piezoelectric element holding portion 32 is integrally provided in a region corresponding to the row of the pressure generating chambers 12, but may be provided independently for each piezoelectric element 300.
Examples of the material of the bonding substrate 30 include glass, a ceramic material, a metal, a resin, and the like, but it is more preferable that the bonding substrate 30 is formed of substantially the same material as the thermal expansion coefficient of the flow path forming substrate 10. In the embodiment, it is formed using a silicon single crystal substrate made of the same material as the flow path forming substrate 10.

  In addition, the bonding substrate 30 is provided with a reservoir 31 in a region corresponding to the ink supply path 13 of the flow path forming substrate 10. The reservoir portion 31 is provided with the bonding substrate 30 in the thickness direction along the row of the pressure generation chambers 12, and is communicated with the ink supply path 13 and the through hole 52 of the flow path forming substrate 10 to each pressure generation chamber. A manifold 200 serving as 12 common ink chambers is formed.

  In addition, on the bonding substrate 30, a wiring pattern to which a driving signal is supplied by connecting an external wiring (not shown) is provided. A driving IC 400 that is a semiconductor integrated circuit (IC) for driving each piezoelectric element 300 is mounted on the wiring pattern.

  The drive signal includes, for example, a drive system signal for driving the drive IC 400 such as a drive power supply signal, and various control system signals such as a serial signal (SI), and a plurality of wiring patterns are supplied with the respective signals. Consists of wiring.

  The lower electrode 60 is formed in a region facing the pressure generation chamber 12 in the longitudinal direction of the pressure generation chamber 12, and is continuously provided in a region corresponding to the plurality of pressure generation chambers 12. Further, the lower electrode 60 extends to the outside of the row of the pressure generating chambers 12.

  An extraction electrode 90 is connected near one end of the upper electrode 80. The drive IC 400 and the extraction electrode 90 extended from each piezoelectric element 300 are electrically connected to each other by a connection wiring 220 made of a conductive wire such as a bonding wire, for example. Similarly, the drive IC 400 and the lower electrode 60 are electrically connected by a connection wiring (not shown).

  Further, a compliance substrate 40 including a sealing film 41 and a fixing plate 42 is bonded onto the bonding substrate 30. Here, the sealing film 41 is made of a material having low rigidity and flexibility (for example, a polyphenylene sulfide (PPS) film having a thickness of 6 μm), and the sealing film 41 seals one surface of the reservoir portion 31. It has been stopped. The fixing plate 42 is made of a hard material such as metal (for example, stainless steel (SUS) having a thickness of 30 μm). Since the region of the fixing plate 42 facing the manifold 200 is an opening 43 that is completely removed in the thickness direction, only one surface of the manifold 200 is a flexible sealing film 41.

  In the ink jet recording head 1, after taking ink from the ink supply means and filling the interior from the manifold 200 to the nozzle opening 21 with the ink, each of the bottoms corresponding to the pressure generating chambers 12 according to the recording signal from the driving IC 400. A voltage is applied between the electrode 60 and the upper electrode 80. By applying voltage, the elastic film 50 and the piezoelectric body 70 are bent and deformed, the pressure in each pressure generating chamber 12 is increased, and ink droplets are ejected from the nozzle openings 21.

Hereinafter, the manufacturing method of the ink jet recording head 1 will be described with reference to FIGS. 4 to 10, focusing on the manufacturing method of the piezoelectric actuator 100 in the present embodiment.
FIG. 4 is a flowchart illustrating a method for manufacturing the ink jet recording head 1, and FIGS. 5 to 10 are cross-sectional views in the longitudinal direction of the pressure generating chamber 12.
The ink jet recording head 1 is obtained by separating each ink jet recording head 1 after forming a plurality of ink jet recording heads 1 in a wafer state. 5 to 10 show part of a cross-sectional view in the process of forming the ink jet recording head 1.

4, the manufacturing method of the ink jet recording head 1 includes step 1 (S1) as a diaphragm forming process, step 2 (S2) as a lower electrode forming process, and step 3 (as a piezoelectric layer forming process). S3), Step 4 (S4) as the upper electrode film forming step, Step 5 (S5) as the piezoelectric element forming step, Step 6 (S6) as the etching step, and Step 7 as the lead electrode forming step. (S7), Step 8 (S8) as the bonding substrate bonding step, and Step 9 (S9) as the flow path forming substrate etching step are included.
Here, the manufacturing method of the piezoelectric actuator 100 includes a diaphragm forming step (S1), a lower electrode forming step (S2), a piezoelectric layer forming step (S3), an upper electrode film forming step (S4), and a piezoelectric device. It includes an element formation step (S5), an etching step (S6), and an extraction electrode formation step (S7).

FIG. 5A and FIG. 5B show the diaphragm forming step (S1).
In FIG. 5A, a flow path forming substrate wafer 110, which is a silicon wafer, is thermally oxidized in a diffusion furnace at about 1100 ° C., and an elastic film 50 containing silicon dioxide is formed on the surface thereof. For example, a relatively thick and rigid silicon wafer having a thickness of about 625 μm can be used as the flow path forming substrate wafer 110.

In FIG. 5B, an insulator film 51 made of zirconium oxide (ZrO ₂ ) is formed on the elastic film 50 on one side of the flow path forming substrate wafer 110. Specifically, after a zirconium (Zr) layer is formed on the elastic film 50 by, for example, sputtering, the zirconium layer is made of zirconium oxide by thermal oxidation in a diffusion furnace at 500 to 1200 ° C., for example. An insulator film 51 is formed. The elastic film 50 and the insulator film 51 form a diaphragm 53.
The diaphragm may have a single layer structure, or may be composed of a material other than silicon dioxide or zirconium oxide.

FIG. 5C and FIG. 5D show the lower electrode formation step (S2).
In FIG. 5C, a lower electrode film 600 made of platinum (Pt), iridium (Ir) or the like is formed on the entire surface of the insulator film 51. The lower electrode film 600 may have a laminated structure. For example, a stacked structure in which platinum and lithium are stacked can be used.
Thereafter, in FIG. 5D, the lower electrode 60 is obtained by patterning into a predetermined shape. At this time, the lower electrode films 61 and 62 of the step adjusting portions 310 and 320 shown in FIGS. 2 and 3 are also formed.

6E, in the piezoelectric layer forming step (S3), a piezoelectric layer 700 made of a piezoelectric material is formed on the lower electrode 60, the lower electrode films 61 and 62, and the insulator film 51. As the piezoelectric material, lead zirconate titanate (PZT) can be used.
As a method of manufacturing the piezoelectric layer 700, a so-called sol in which a so-called sol in which a metal organic substance is dissolved and dispersed in a catalyst is applied, dried, gelled, and fired at a high temperature to obtain a piezoelectric layer 700 made of metal oxide -A gel method can be used.
The method is not limited to the sol-gel method, and for example, a MOD (Metal Organic Decomposition) method or the like may be used.

The sol-gel method will be described in detail. First, a sol (solution) containing a metal organic compound is applied. Next, the piezoelectric precursor film obtained by coating is heated to a predetermined temperature and dried for a predetermined time, and the sol solvent is evaporated to dry the piezoelectric precursor film. Further, the piezoelectric precursor film is degreased at a constant temperature for a predetermined time in an air atmosphere.
Here, degreasing refers, the organic components of the sol film, for example, is to be detached as _{NO 2, CO 2, H 2} O or the like.

By repeating such coating, drying, and degreasing processes a predetermined number of times, for example, twice, a piezoelectric precursor film is formed to a predetermined thickness, and this piezoelectric precursor film is heated in a diffusion furnace or the like. To form a piezoelectric film. That is, by firing the piezoelectric precursor film, crystals grow and a piezoelectric film is formed.
The firing temperature is preferably about 650 to 850 ° C., for example, the piezoelectric precursor film is fired at about 700 ° C. for 30 minutes to form the piezoelectric film. Crystals of the piezoelectric film formed under such conditions are preferentially oriented in the (100) plane.
By repeating the coating, drying, degreasing, and firing steps described above a plurality of times, a piezoelectric layer 700 having a predetermined thickness made of a multilayer piezoelectric film is formed.

  As the material of the piezoelectric layer 700, for example, a relaxor ferroelectric material in which a metal such as niobium, nickel, magnesium, bismuth or yttrium is added to a ferroelectric piezoelectric material such as lead zirconate titanate may be used. .

  In FIG. 6F, in the upper electrode film forming step (S4), after forming the piezoelectric layer 700, an upper electrode film 800 made of, for example, iridium, gold (Au) or the like is formed on the entire surface of the piezoelectric layer 700. To do. The upper electrode film 800 can be formed by a sputtering method, for example, a DC or RF sputtering method.

  The piezoelectric element forming step (S5) is shown in FIGS. 6 (g), 6 (h), 7 (i), and 7 (j).

The piezoelectric element forming step (S5) can be performed by a photolithography step.
In FIG. 6G, a resist is applied on the upper electrode film 800 to form a resist film 500.
6H, resist films 510, 520, and 530 are left by development in regions where the piezoelectric element 300 and the step adjustment portions 310 and 320 shown in FIGS. 2 and 3 are formed.

In FIG. 7I, the upper electrode film 800 and the piezoelectric layer 700 are etched by dry etching such as reactive ion etching or ion milling to form the piezoelectric element 300 and the step adjustment parts 310 and 320.
In FIG. 7J, the resist films 510, 520, and 530 are removed.

FIG. 7 (k-1) and FIG. 8 (k-2) show the etching step (S6). FIG. 7 (k-1) is a view corresponding to the AA cross section in FIG. 3 (a). FIG. 8K-2 is a view corresponding to the BB cross section in FIG.
7 (k-1) and 8 (k-2), in the etching step (S6), the slit 91 shown in FIGS. 2 and 3 is formed. The slit 91 is formed by etching the diaphragm 53 between the extraction electrodes 90 to be formed later along the extraction electrodes 90.
The etching step (S6) can be performed using a photolithography step, similarly to the piezoelectric element forming step (S5).
In the embodiment, the etching step (S6) is performed at the same time as the step of forming the slit 311 (shown in FIGS. 2 and 3) for relaxing the stress of the upper electrode film 81 of the step adjustment unit 310. Can do. Etching is performed under the condition that the upper electrode film 81 is removed and the diaphragm 53 is not removed.
Note that the etching step (S6) may not be performed simultaneously with the step of forming the slit 311. For example, the slit 91 may be formed by performing the etching step (S6) after the extraction electrode forming step (S7). In this case, a new process is required.

8 (l) and 8 (m) show the extraction electrode forming step (S7).
In FIG. 8L, the metal layer 900 is formed over the entire surface of the flow path forming substrate wafer 110. The main material constituting the extraction electrode 90 is not particularly limited as long as it is a material having relatively high conductivity, and examples thereof include gold, aluminum, and copper. Also, a two-layer structure using NiCr as the underlayer or a multilayer structure may be used.
In FIG. 8M, the extraction electrode 90 is formed by patterning the metal layer 900 for each upper electrode 80 that is an individual electrode of the piezoelectric element 300 through a mask pattern (not shown) made of resist or the like.

In FIG. 9 (n), in the bonding substrate bonding step (S8), the bonding substrate wafer 130, which is a silicon wafer and becomes a plurality of bonding substrates 30, is bonded to the piezoelectric element 300 side of the flow path forming substrate wafer 110 with an adhesive. 35 is used for bonding. As the adhesive 35, for example, an epoxy-based adhesive can be used. In the bonding substrate wafer 130, a reservoir portion 31, a piezoelectric element holding portion 32, and the like are formed in advance.
In addition, since the bonding substrate wafer 130 has a thickness of, for example, about 400 μm, the rigidity of the flow path forming substrate wafer 110 is significantly improved by bonding the bonding substrate wafer 130.
Further, by providing the step adjustment portions 310 and 320, it is not necessary to increase the thickness of the adhesive 35, and it is possible to suppress dust generated due to protrusion of the adhesive 35 and to suppress generation of stress due to the increase in the thickness of the adhesive 35.

FIG. 9 (o) to FIG. 10 (r) show the flow path forming substrate etching step (S9).
In FIG. 9 (o), after the flow path forming substrate wafer 110 is polished to a certain thickness, the flow path forming substrate wafer 110 is made to have a predetermined thickness by wet etching with hydrofluoric acid. For example, the flow path forming substrate wafer 110 can be etched to have a thickness of about 70 μm.

10 (p) and 10 (q), a mask film 54 made of, for example, silicon nitride (SiN) is newly formed on the flow path forming substrate wafer 110 and patterned into a predetermined shape. Then, the flow path forming substrate wafer 110 is anisotropically etched through the mask film 54 to form the pressure generating chamber 12, the communication portion 14, the ink supply path 13, and the like in the flow path forming substrate wafer 110. .
Specifically, by etching the flow path forming substrate wafer 110 with an etchant such as a potassium hydroxide (KOH) aqueous solution until the elastic film 50 is exposed, the pressure generating chamber 12, the communication portion 14, and the ink The supply path 13 is formed at the same time.

In FIG. 10 (r), the diaphragm 53 composed of the elastic film 50 and the insulator film 51 is removed by wet etching from the ink supply path 13 side to form a through hole 52. The reservoir unit 31 and the ink supply path 13 are communicated with each other through the through hole 52 to constitute the manifold 200.
Next, the mask film 54 on the surface of the flow path forming substrate wafer 110 is removed.

After the manifold 200 is formed, the drive IC 400 is mounted, and the drive IC 400 and the extraction electrode 90 are connected by the connection wiring 220 (see FIG. 3).
Thereafter, unnecessary portions of the outer peripheral edge portions of the flow path forming substrate wafer 110 and the bonding substrate wafer 130 are removed by cutting, for example, by dicing. Then, the nozzle plate 20 having the nozzle openings 21 formed on the surface of the flow path forming substrate wafer 110 opposite to the bonded substrate wafer 130 is bonded, and the bonded substrate wafer 130 has flexibility. A compliance substrate 40 in which a sealing film 41 as an elastic film and a fixing plate 42 as a pressing substrate made of a metal material such as SUS are laminated is bonded.
The ink jet recording head 1 having the above-described structure is manufactured by dividing the flow path forming substrate wafer 110 and the like into a single chip size flow path forming substrate 10 and the like as shown in FIGS. .

Hereinafter, a case where particles are dropped from the dry etching apparatus and adhered between the extraction electrodes 90 formed later in the piezoelectric element forming step (S5) will be described with reference to FIGS.
Particles adhered after the formation of the upper electrode film 800 and before and during dry etching are particularly problematic. Hereinafter, a case where particles adhere after the resist films 510, 520, and 530 are left by development will be described.

FIG. 11 is a partial plan view in the state of FIG. The extraction electrode 90, the slit 91, and the slit 311 to be formed later are indicated by a two-dot chain line.
FIG. 12 shows a partial cross-sectional view in the state of FIG. 12A is a partial cross-sectional view taken along the line BB in FIG. 11, and FIG. 12B is a partial cross-sectional view taken along the line CC in FIG.
Each of FIGS. 13, 14, 15, and 16 is a partial cross-sectional view taken along the line BB in FIG. 11 as in FIG. 12, and each of FIG. 13, FIG. 14, FIG. 15, and FIG. (B) is CC partial sectional drawing in FIG. 11 similarly to FIG. In addition, in FIG. 12B, FIG. 13B, and FIG. 14B, the position where the extraction electrode 90 is formed is indicated by a two-dot chain line.
In FIG. 11 and FIG. 12B, the particles P are attached over the extraction electrode 90 to be formed later.

FIG. 13 is a partial cross-sectional view in the state of FIG.
In FIG. 13, when dry etching is performed, the piezoelectric layer 700 and the upper electrode film 800 shown in FIG. 12 where the particles P are attached cause an etching residue, and the remaining etching piezoelectric layer 73 and the remaining etching upper electrode film 83. It becomes.

FIG. 14 is a partial cross-sectional view in the state of FIGS. 7 (k-1) and 8 (k-2).
In FIG. 14, when the slit 91 is formed at the same time as the process of forming the slit 311 in order to relieve the stress of the upper electrode film 81 of the step adjusting unit 310, the slit 92 is also formed in the etching remaining upper electrode film 83. The Etching is performed under the condition that the etching residual upper electrode film 83 is removed. Therefore, the etching residual upper electrode film 83 is divided into two by the slit 92.

FIG. 15 is a partial cross-sectional view in the state of FIG.
In FIG. 15, when the metal layer 900 is formed over the entire surface of the flow path forming substrate wafer 110, the metal layer 900 is also formed in the slits 91 and 92.

FIG. 16 is a partial cross-sectional view in the state of FIG.
In FIG. 16, when the metal layer 900 is patterned for each upper electrode 80 that is an individual electrode of the piezoelectric element 300, the extraction electrode 90 is formed so as to cover the remaining etching piezoelectric layer 73 and the remaining etching upper electrode film 83.

According to such an embodiment, there are the following effects.
(1) After the piezoelectric element formation step (S5), in the etching step (S6), at least part of the diaphragm 53 between the extraction electrodes 90 formed in the subsequent extraction electrode formation step (S7) Etching is performed under the condition that the film 83 is removed and the diaphragm 53 is not removed. In the piezoelectric element forming step (S <b> 5), even if an etching residual upper electrode film 83 is generated between the extraction electrodes 90, the extraction residual upper electrode film 83 is divided by etching and is formed on the etching residual upper electrode film 83. Insulation between the electrodes 90 can be maintained. Therefore, it is possible to obtain a method for manufacturing the piezoelectric actuator 100 in which defective driving of the piezoelectric actuator 100 caused by a short circuit between the extraction electrodes 90 is reduced.

  (2) After the piezoelectric element forming step (S5), the slits 91 and 92 are formed along the extraction electrode 90 between the extraction electrodes 90. Therefore, the etching residual upper electrode film 83 is generated between the extraction electrodes 90. However, the upper electrode film 83 after etching is divided, and insulation between the extraction electrodes 90 can be maintained. Therefore, it is possible to obtain a method of manufacturing the piezoelectric actuator 100 in which the drive failure of the piezoelectric actuator 100 caused by the short circuit between the extraction electrodes 90 is further reduced.

  (3) In the piezoelectric actuator 100 in which the lower electrode 60 formed on the diaphragm 53 is a common electrode and the upper electrode 80 formed on the piezoelectric body 70 is an individual electrode, a manufacturing method of the piezoelectric actuator 100 having the above-described effect is provided. Can be obtained.

Various modifications other than the embodiment can be made.
For example, a protective layer may be formed after the piezoelectric element forming step (S5) in order to protect the exposed piezoelectric body from moisture or the like. For example, Al ₂ O ₃ can be used as the protective layer. The etching step (S6) may be performed before forming the protective layer, or may be performed after forming the protective layer. Even if a pinhole or the like is generated in the protective layer, the effect in the embodiment can be obtained.
When the upper electrode is used as a common electrode, the upper electrode serves as a protective layer, so that it is less necessary to form a new protective layer.

In the above-described embodiments, the ink jet recording head has been described as an example of the liquid ejecting head. However, the present invention is widely applied to all liquid ejecting heads, and ejects liquid other than ink. Of course, it can also be applied to the head.
Other liquid ejecting heads include, for example, various recording heads used in image recording apparatuses such as printers, color material ejecting heads used in the manufacture of color filters such as liquid crystal displays, organic EL displays, and FEDs (field emission displays). Examples thereof include an electrode material ejection head used for electrode formation, a bioorganic matter ejection head used for biochip production, and the like.
Furthermore, the present invention can be applied not only to a piezoelectric actuator mounted on a liquid ejecting head as pressure generating means but also to a piezoelectric actuator mounted on any device. For example, the piezoelectric actuator can be applied to a sensor or the like in addition to the head described above.

  DESCRIPTION OF SYMBOLS 12 ... Pressure generation chamber, 13 ... Ink supply path, 14 ... Communication part, 31 ... Reservoir part, 32 ... Piezoelectric element holding part, 35 ... Adhesive, 50 ... Elastic film, 51 ... Insulator film, 53 ... Diaphragm, 54 ... Mask film, 60 ... Lower electrode, 61 ... Lower electrode film, 62 ... Lower electrode film, 70 ... Piezoelectric body, 71 ... Piezoelectric layer, 72 ... Piezoelectric layer, 73 ... Piezoelectric layer, 80 ... Upper electrode, DESCRIPTION OF SYMBOLS 81 ... Upper electrode film, 82 ... Upper electrode film, 83 ... Upper electrode film, 90 ... Extraction electrode, 91, 92 ... Slit, 100 ... Piezoelectric actuator, 110 ... Wafer for flow path formation substrate, 130 ... Wafer for bonding substrate, DESCRIPTION OF SYMBOLS 300 ... Piezoelectric element, 310 ... Step adjustment part, 311 ... Slit, 320 ... Step adjustment part, 510 ... Resist film, 520 ... Resist film, 530 ... Resist film, 600 ... Lower electrode film, 700 ... Piezoelectric layer, 800 ... Upper electrode film, 900 ... metal .

Claims (4)

A method of manufacturing a piezoelectric actuator comprising a piezoelectric element having either a lower electrode or an upper electrode as an individual electrode and an extraction electrode drawn from the individual electrode,
A lower electrode film forming step of forming a lower electrode film on the substrate;
A piezoelectric layer forming step of forming a piezoelectric layer on the lower electrode film;
An upper electrode film forming step of forming an upper electrode film on the piezoelectric layer;
The piezoelectric layer including the piezoelectric body and either the lower electrode or the upper electrode as the individual electrode is formed by selectively etching the piezoelectric layer and the lower electrode film or the upper electrode film. And forming a step adjustment part having the same layer structure as the piezoelectric element for adjusting the bonding height between the substrate and the bonding element having a space that does not hinder the movement of the piezoelectric element by sealing the piezoelectric element. Process,
An extraction electrode forming step of forming the extraction electrode respectively extracted from the individual electrode ,
A method of manufacturing a piezoelectric actuator, further comprising an etching step of simultaneously forming slits between the extraction electrodes and in the upper electrode film of the step adjustment portion . In the manufacturing method of the piezoelectric actuator of Claim 1 ,
In the piezoelectric element forming step, the lower electrode is formed as a common electrode, and the upper electrode is formed as the individual electrode . A lower electrode film formed on the substrate;
A piezoelectric layer formed on the lower electrode film;
An upper electrode film formed on the piezoelectric layer;
A piezoelectric element provided with either one of the lower electrode film or the upper electrode film as an individual electrode;
A step adjustment unit that adjusts the bonding height between the substrate and the bonding substrate having a space that seals the piezoelectric element and does not hinder the movement of the piezoelectric element, and includes the lower electrode, the piezoelectric layer, and the upper electrode. When,
Each including an extraction electrode extracted from the individual electrode,
A slit formed in the upper electrode film of the step adjustment section;
A slit formed in the upper electrode film between the extraction electrodes;
A piezoelectric actuator further comprising: The piezoelectric actuator according to claim 3, wherein
  The piezoelectric actuator, wherein the lower electrode is a common electrode.

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